Engineering Drawing Basics

Engineering drawings: common features
Drawings convey the following critical information:
Geometry – the shape of the object; represented as views; how the object will look when it is viewed from various standard directions, such as front, top, side, etc.
Dimensions – the size of the object is captured in accepted units.
Tolerances – the allowable variations for each dimension.
Material – represents what the item is made of.
Finish – specifies the surface quality of the item, functional or cosmetic. For example, a mass-marketed product usually requires a much higher surface quality than, say, a component that goes inside industrial machinery.

Line styles and types
A variety of line styles graphically represent physical objects. Types of lines include the following:
Visible – are continuous lines used to depict edges directly visible from a particular angle.
Hidden – are short-dashed lines that may be used to represent edges that are not directly visible.
Center – are alternately long- and short-dashed lines that may be used to represent the axes of circular features.
Cutting Plane – are thin, medium-dashed lines, or thick alternately long- and double short-dashed that may be used to define sections for section views.
Section – are thin lines in a pattern (pattern determined by the material being "cut" or "sectioned") used to indicate surfaces in section views resulting from "cutting." Section lines are commonly referred to as "cross-hatching."
*A line style is also called the alphabet of lines.

Orthographic projection
The orthographic projection shows the object as it looks from the front, right, left, top, bottom, or back, and are typically positioned relative to each other according to the rules of either first-angle or third-angle projection.
First angle projection is the ISO standard and is primarily used in Europe. The 3D object is projected into 2D "paper" space as if you were looking at an X-ray of the object: the top view is under the front view, the right view is at the left of the front view.
Third angle projection is primarily used in the United States and Canada, where it is the default projection system according to BS 8888:2006, the left view is placed on the left and the top view on the top.
Not all views are necessarily used, and determination of what surface constitutes the front, back, top and bottom varies depending on the projection used.

Isometric projection
The isometric projection show the object from angles in which the scales along each axis of the object are equal. Isometric projection corresponds to rotation of the object by ± 45° about the vertical axis, followed by rotation of approximately ± 35.264° [= arcsin(tan(30°))] about the horizontal axis starting from an orthographic projection view. "Isometric" comes from the Greek for "same measure." One of the things that makes isometric drawings so attractive is the ease with which 60 degree angles can be constructed with only a compass and straightedge.
Isometric projection is a type of axonometric projection. The other two types of axonometric projection are:
Dimetric projection
Trimetric projection

Oblique projection
An oblique projection is a simple type of graphical projection used for producing pictorial, two-dimensional images of three-dimensional objects:
it projects an image by intersecting parallel rays (projectors)
from the three-dimensional source object with the drawing surface (projection plan).
In both oblique projection and orthographic projection, parallel lines of the source object produce parallel lines in the projected image.

Perspective
Perspective is an approximate representation on a flat surface, of an image as it is perceived by the eye. The two most characteristic features of perspective are that objects are drawn:
Smaller as their distance from the observer increases
Foreshortened: the size of an object's dimensions along the line of sight are relatively shorter than dimensions across the line of sight.

Webpage:
http://en.wikipedia.org/wiki/Engineering_drawing

Quiz 6

Quiz 5

Quiz 4

Quiz 3

Quiz 2

Hands-On AutoCAD LT Quiz

http://highered.mcgraw-hill.com/sites/007861791x/student_view0/chapter6/practice_quiz_1.html

Journal: Week 4

Monday Feb 22/10:
Today we basically just worked on the roller coasters, Finished the "paper work" and the brief, started working on the track, developing the beams of the coaster.

Tuesday Feb 23/10:
Completed the first AutoCAD LT Practice Quiz, and worked on the roller coaster. Im having some trouble working with the angling of the beams but I'll get the hang of it eventually.

Wednesday Feb 24/10:
Worked a lot on the roller coaster today, made a lot of progress, starting to work on the first incline of the coaster.

Thursday Feb 25/10:
Worked a lot on the initial incline of the coaster again, having some difficulty but I'll get it.

Friday Feb 26/10:
Still having troubles with the incline, just because of the rotations, I might work on it at home.

Roller Coaster Design Statement/Brief

The Roller Coaster design requires:

• an initial drop at approximately 40-80 meters
• at least one loop
• at least one hill
• as many desired bends
• a theme,
• an electric motor to bring the car to the initial drop
• No other external forces except gravity
• No more than 6Gs of force should be experienced

Key Designs:

The Coaster will have an initial height 0f 80m (262ft.)

The initial hill will slightly curve

There will be a small but quick incline and downward slope

The final hill will be sizeable

The loop will deliver the final excitement before the end of the ride.

Google SketchUp: Dodge Charger Model (Incomplete)

This project was simple at first but I encounter some difficulty with the tools, there were set-backs.

WHMIS Final Exam

Journal: Week 3

Tuesday Feb 16/10:
Took a note on Oblique and Isometric drawings, as well as single and two point perspectives.
Worked on the Charger model more, everything selected except the rear view.

Wednesday Feb 17/10:
Continued working on the Charger Model, wrote the WHMIS final exam

Thursday Feb 18/10:
Posted whatever I had finished of the Dodge Charger Model, researched info about rollercoasters, looked at examples.

Friday Feb 19/10:
Researched Roller coasters, looked at the brief and paperwork and started the design of our roller coaster.

Artistic Drawing/Perspective

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Single Point Perspective:
Used when drawing 3D objects. In a single perspective, all of the objects points are determined by the position of the vanishing point (VP)

Two point perspective:
The vanishing points are located on the horizon line. the positioning of the horizon line

Isometric:
This type of drawing involves objects projected at 30 degrees.

Oblique:
Involves the drawing of an object in 3 dimensions, the base of the object is parralel to the base(horizon) of the image.

The most complicated project so far, used trim and offset again, worked with dimentions.

Journal: Week 2

Monday Feb 08/10:
We completed the metric/imperial measurements pages, began working on the mechanical drawings on CAD

Tuesday Feb 09/10:
We started the day working on the mechanical drawings, seemed difficult at first but actually really easy, just using offset and trim.

Wednesday Feb 10/10:
Finished the Mechanical Drawing:Reading Dimensions, really easy once you get the hang of it, once again used trim and offset and got to work with dimensions.

Thursday Feb 11/10:
Started to work with the Google SketchUp program, going to draw a car, the Charger, pretty cool seems complicated but i'll get the hang of it.

Friday Feb 12/10
Worked on the Google SketchUp program, making a dodge charger, outlined the model so far, further work required.

ACAD4 AM

Definitely more challenging than the first CAD projects, using the offset and trim techniques

ACAD2 AM

My second CAD project, using Polar coordinates.

CAD Trial 1

this was my first CAD drawing, pretty awesome

Journal: Week 1

Friday Feb 05/10:
Finished the ACAD4 projects, seemed hard but once you get used to it its so easy. starting the more complex work.

Thursday Feb 04/10:
Finished 2 CAD projects, easy stuff, using polar coordinates.
Mr. D explained the concepts of Trim and Offset, started working with the new project ACAD4

Wednesday Feb, 03/10:
Discussed the properties of CAD, Learned about coordinates
Seems pretty easy.
We started our CAD drawing, doesnt seem that difficult

Tuesday Feb 02/10:
Mr. D described the basics of CAD.
Learned how to set up a blog, to record stuff we learn.
Learned basic drawing equipement

BASIC DRAWING EQUIPMENT

Drawing Pencils: Basic drawing tool, varies in thickness of lead(2B-2H)
Refillable Pencil: constant thickness of line.
Ink fountain pens: Used for fancy styles of writing.
Protractor: Is used to measure angles
Compass: Draw archs and circles

Fine Pen: Permanent, accurate lines
T-Squares: Used for drawing permanent horizontal lines
Set Squares: Used to draw accurate angles
Ruler: Used to measure distances with lines being drawn with T-Squares and Set Squares.
Flexi-curve: Used to draw curves. It can be formed into almost any curve as it is flexible.
Exploded View: Displays how to assemble

http://www.technologystudent.com/designpro/drawdex.htm